Catalytic desulfurization of kerosene and white spirits



Nov. 6, 1951 F. w. B. PORTER ET AL 2,574,445

CATALYTIC DESULFURIZATION OF KEROSENE AND WHITE SPIRITS Filed Aug. 27, 1948 wm/cx will/hm 3mm FORTE! PAM/r koKExT (150 5: 6,95

Divan/r0 A TTO/i N575 Patented Nov. 6, 1951 CATALYTIC DESULFURIZATION OF KERO.-..

SENE' AND-WHITE. SPIRITS.

Frederick William Bertram Porter and Frank Robert GeorgeGreen, Sunbury on" Thames; England; assignors'to AngIo-Iranian-OiI Com pany Limited; London, England, a Britislijoi'ntstock corporation? Application August 27, 1948;SiialNoT 46 ,502"

In Great Britain August 26;"1947' This'mvention relatesto the catalytic 'desul-r.

phurisation ofkerosene and: white spirits.=

Known processes for theacatalytic 'desulphuri-' sation-of kerosene and white spirits, wherein organicsulphur compounds are .reduced byhydrd- 5 800 F., dehydrogenation occurs to such an exgen'tohydrogen-sulphideyare carried out=undertent that the product be'comes increasingly aroconditionswhich result in a net-consumption of maticzf' Furthermore,'attemperatures above 800 hydrogemproportional *to r-thefamount of sulphur F. the on-stream time is reduced: The preferred removed andvto --theotherside: reactions which temperature of operation is to some extent demay---take place, such,for-example,as thevhypendent upon the pressure' 'employed which is drogenationofaromatics. It is, therefore, neces-- preferably between 50 and 250 lb./sq. in. As the saryto provide hydrogen from ran-extraneous pressure is increased,the-minimumtemperature source in ordertocarry out such known processes. at" which satisfactory dehydrogenation "of the It -hasnow been found-thatthecatalytic -de naphthenes can-be obtained'increases;and if *at sulphurisationof kerosenesandwhite-spirits can a fixedtemperature the-pressure is "sufiiciently" becarriedout without theneed for added hydro? increased; the reverse'reaction of hydrogenation genandethatvthe process canbe operated to proof aromatics begins to occur? Thus, when operducea net. yield. of hydrogenwhich can be used ating at 'the higherpressures it is preferable to' in other hydrogenation processes. use higher temperatures Similarly it is desir- According tothe invention, .the.desulphurisaable to avoid the combination of' high temperationrof a petroleum fraction boiling within the ture and low pressuresince such conditions lead range-of about 150 to 240v C. is effectedby passto a short on'-str'eam time for satisfactory operaing the fraction in vapour form over a catalyst tion. By' operating under the optimum condi-' which under the reaction conditions employed tions, on-stream" times -'of '300=to"400 hrs.-'before" combinesactivity for dehydrogenationtof vnaphv regeneration are possible. i thene molecules to aromatics, with activity for The space'velocitymay bevaried according to theconye'rsion of organically combined. sulphur. the degree of desulphurisation required and the to "hydrogensulphide and which is not poisoned." activity of the'catalyst'bu't space velocities above as a catalyst by the presence" of Sulphurcom l0'v./v.'/hri result 'in'a low degree ofdesulphurpounds; at :a temperatureand ata pressure such isation'. that'a considerable proportion of thecombined Operating under the conditions above desulphur contained in the fraction 'is converted scribed, the'ga's'esseparated by cooling the treatinto hydrogen sulphide and hydrogen is produced ed fractionat reaction 'pressure contain '70 to by" dehydrogenation of-some' of the naphthen'es 80% by volume'bf hydrogen and are continucontained inthe fractio'n'in' an amountexceed 3 ouslyrecycled to'the reaction zone. It has been ingthat required to effect said conversion of the found that the hydrogen-sulphide content of combined sulphur contained in the fraction into the separated"gasbriild'up to'an' equilibrium hydrogensulphide, separating hydrogen sulphide concentrationwhereafter thegases may be-recyand a hydrogen-rich gas mixture from the" cled to the reaction zone'without further intreated' fraction, and recycling sai'd" hydrogen-Q 40 crease "in' the content of hydrogen sulphide which rich gas mixture'to the reaction zone to c0nsti= is thereafter"dissolved in""the-product untilsuch tute th' whole ofthezhydrogen supplied to said time as it is depressurised. If desired, however; zone'and' at a rate sufficient to maintain the neethe.hydrogensulphidemay be removed from the essary partial pressure of hydrogen thereina gasby any of the usuatmethods and the hydro- It is believed thatthe' reaction proceeds by gen sulphide-free.gasurecycled to the reaction dehydrogenation ofsome sof the =naphthnes to zone; Th""gas may be submitted to treatproduce-;hydrogen in'excess'of that required to ment for increasing the relative proportion of convert the combined sulphur presentinto hydrogen therein; as by passagethrough an oil drogenz-sulphide and the: reaction'conditions for tower. It is not necessary to supply extraneous any particular feedstock must threfOr'e be dehydrogen to threaction zone when starting the.

termined having regard to any limiting conditions imposed: :by these: two reactions. Thus,

therevis a lower:temperature' 'of about" 7O0 -F.-

depends" to some-extent ioir the sulphur content and th'e higher -the':sulphur: content, the higher- I theiiminimum temperature necessaryto provide sufficient hydrogeni it At' temperatures above about process ast'h gases separated from the treated fraction may be' allowed to buildup to form the recycle gasivi.

Among the catalysts'flithat:-may"be' used are' an'dxbelow which the reaction would not be seli metal sulphide and oxides especially thoseof'the supporting'in hydrogen: wThi'slower temperaturetungsten sulphide) or in admixture with other sulphides or oxides (e. g. pellets consisting of two parts tungsten sulphide and one part nickel sulphide) or in combination with other oxides or sulphides (e. g. cobalt molybdate or thiomolybdate) or mixed with or deposited on a porous support such as natural or processed bauxite, activated alumina and kieselguhr. Natural and processed bauxite may themselves be used as catalysts. The preferred catalyst consists of cobalt molybate supported on alumina.

An effective pelleted catalyst was prepared by mixing powdered cobalt oxide, molybdic oxide and alumina and pelleting with 1% graphite into 1 3'" pellets which were then treated for two hours at 550 C. The catalyst could also be prepared by extrusion.

An eifective cobalt molybdate type catalyst was prepared by the impregnation of roasted bauxite with cobalt molybdate solution so that the molybdenum content of the material stable at 1000 F. was 3-6% by weight while the cobalt content of the material stable at 1000 F. was 1.0% weight.

The process of the invention will now be described by way of example with reference to the accompanying diagram.

Example An unrefined Iranian kerosene having the properties set out in the table below was fed to an autofining chamber I via line H, heat exchanger l2 and prelieater l3 where it was raised to a temperature of 780 F. at 100 lb./sq. in. pressure. The reactor I!) was charged with a catalyst consisting of cobalt molybdate on alumina and the products leaving the reactor, after being passed in heat exchange with the incoming feed in heat exchanger l2 were passed to a cooler [4, where they were cooled under plant pressure, and then to a gas separator [5. The gases leaving the separator through line I6 were recycled to the reaction zone, in admixture with the incoming feed, via the booster l1, excess gas being vented from the system via line 18. The cooled liquid product from the separator l5, which contained all the H28 in solution, was then reduced to atmospheric pressure in a further separator I9 in which the bulk of the H28 was separated and removed from the system via line 20. The desulphurised product was removed via line 2|. Gas was recycled to the preheater at a rate of 4000 cu. ft./bbl. The gas make amounted to 60 cu. ft./bbl. consisting of 70-80% by volume hydrogen which was more than suflicient to maintain the recycle rate, the surplus gas being vented from the system.

Properties of the feedstock and desulphurised 4 In addition to the fact that the need for an extraneous source of hydrogen is obviated, the process of the invention as applied to kerosene yields a saturated product of low sulphur content, sweet smelling and of low char value, while as applied to white spirits it yields a saturated product of good odor, low sulphur content and improved quality for use, for example, as a solvent. Furthermore, the process of the invention range of about ISO-240 0., wherein the fraction is passed in vapor form to a reaction zone wherein it is contacted in the presence of hydrogen and at elevated temperature and pressure with a dehydrogenation-hydrogenation catalyst which i immune to sulphur poisoning and combines activity for the dehydrogenation of naphthenes to aromatics with activity for the hydrogenation of organicall combined sulphur in the fraction to hydrogen sulphide, and wherein the treated fraction is removed from the reaction zone and the hydrogen sulphide subsequently removed therefrom, the method of operating the process so that it will be self-supporting with respect to the amount of hydrogen needed and produce product oil having, except for lowered sulphur content, properties and boiling range substantially the same as the feedstock, comprising the steps of passing the fraction to be treated through said reaction zone and contacting the fraction therein with said catalyst and with hydrogen derived solely from the oil, maintaining a selected temperature in said zone between about 700 F, to about 800 F. at which hydrogen is produced continuously from said fraction, maintaining a .selected pressure in said zone between about 50 to about 250 lb./sq. in. gauge, said selected tem perature and pressure being correlated to effect the dehydrogenation of naphthenes contained in the fraction to an extent not substantially in excess of that required to produce sufiicient hya rate sufficient to maintain the necessary partial pressure of hydrogen therein.

'2. A process in accordance with claim 1 wherein said catalyst is of the cobalt-molybdate-onalumina type.

3. A process in accordance with claim 1 in which said selected temperature is approximately 780 F. and said selected pressure is approximately lb./sq. in.

4. A process in accordance with claim 3 where- .in said catalyst is of the cobalt-molybdate-onalumina type.

5. A process in accordance with claim 1 including cooling the products from the reaction zone under substantially the reaction pressure,

. separating the uncondensed hydrogen-rich gas mixture from the liquid condensate of said cooling operation, said condensate containing dissolved hydrogen sulphide, depressuring said liquid condensate to separate a hydrogen sulphide-rich gas from the desired substantially sulphur free liquid product oil, and recycling said hydrogen-rich gas mixture to the reaction zone as the sole source of hydrogen to said zone.

6. A process in accordance with claim 1 in which the space velocity of said fraction is not in excess of about 10 v./v./hr. and in which the hydrogen-rich gas mixture is recycled to said reaction zone at a rate between about 4000 and 6000 cu. ft. per barrel of feedstock.

FREDERICK WILLIAM BERTRAM PORTER. FRANK ROBERT GEORGE GREEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,957,787 Krauch et a1 May 8, 1934 2,000,960 Joseph May 14, 1935 2,037,790 Ipatiefi Apr. 21, 1936 2,315,144 Watson Mar. 30, 1943 2,325,034 Byrns July 27, 1943 2,431,920 Cole Dec. 2, 1947 FOREIGN PATENTS Number Country Date 17,448 Australia Aug. 2, 1929 

1. IN A PROCESS FOR THE HYDROCATALYTIC DESULPHURIZATION OF A SULPHUR-AND-NAPHTHENE-CONTAINING PETROLEUM FRACTION BOILING WITHIN THE RANGE OF ABOUT 150-240* C., WHEREIN THE FRACTION IS PASSED IN VAPOR FORM TO A REACTION ZONE WHEREIN IT IS CONTACTED IN THE PRESENCE OF HYDROGEN AND AT ELEVATED TEMPERATURE AND PRESSURE WITH A DEHYDROGENATION-HYDROGENATION CATALYST WHICH IS IMMUNE TO SULPHUR POISONING AND COMBINES ACTIVITY FOR THE DEHYDROGENATION OF NAPHTHENES TO AROMATICS WITH ACTIVITY FOR THE HYDROGENATION OF ORGANICALLY COMBINED SULPHUR IN THE FRACTION TO HYDROGEN SULPHIDE, AND WHEREIN THE TREATED FRACTION IS REMOVED FROM THE REACTION ZONE AND THE HYDROGEN SULPHIDE SUBSEQUENTLY REMOVED THEREFROM, THE METHOD OF OPERATING THE PROCESS SO THAT IT WILL BE SELF-SUPPORTING WITH RESPECT TO THE AMOUNT OF HYDROGEN NEEDED AND PRODUCE PRODUCT OIL HAVING, EXCEPT FOR LOWERED SULPHUR CONTENT, PROPERTIES AND BOILING RANGE SUBSTANTIALLY THE SAME AS THE FEEDSTOCK, COMPRISING THE STEPS OF PASSING THE FRACTION TO BE TREATED THROUGH SAID REACTION ZONE AND CONTACTING THE FRACTION THEREIN WITH SAID CATALYST AND WITH HYDROGEN DERIVED SOLELY FROM THE OIL, MAINTAINING A SELECTED TEMPERATURE IN SAID ZONE BETWEEN ABOUT 700* F. TO ABOUT 800* F. AT WHICH HYDROGEN IS PRODUCED CONTINUOUSLY FROM SAID FRACTION, MAINTAINING A SELECTED PRESSURE IN SAID ZONE BETWEEN ABOUT 50 TO ABOUT 250 LB./SQ. IN GAUGE, SAID SELECTED TEMPERATURE AND PRESSURE BEING CORRELATED TO EFFECT THE DEHYDROGENATION OF NAPHTHENES CONTAINED IN THE FRACTION TO AN EXTENT NOT SUBSTANTIALLY IN EXCESS OF THEAT REQUIRED TO PRODUCE SUFFICIENT HYDROGEN TO CONVERT THE ORGANICALLY COMBINED SULPHUR INTO HYDROGEN SULPHIDE AND TO MAINTAIN THE PRESSURE IN THE REACTION ZONE, SEPARATING THE PRODUCTS FROM THE REACTION ZONE INTO THE DESIRED LIQUID PRODUCT OIL SUBSTANTIALLY FREE OF SULPHUR, A HYDROGEN SULPHIDE-RICH GAS MIXTURE, AND A HYDROGEN-RICH GAS MIXTURE, THE RECYCLING SAID HYDROGEN-RICH GAS MIXTURE TO THE REACTION ZONE AS THE SOLE SOURCE OF HYDROGEN TO SAID ZONE AND AT A RATE SUFFICIENT TO MAINTAIN THE NECESSARY PARTIAL PRESSURE OF HYDROGEN THEREIN. 